Working Past 65 with Employer Coverage: How Medicare Coordinates with Your Job Benefits

Many people continue working past age 65 -- and if you have employer-sponsored health insurance, you face important decisions about Medicare enrollment. Getting this wrong can result in coverage gaps, late enrollment penalties, or unexpected costs. Here is how to navigate it correctly.

The answer depends primarily on the size of your employer:

Employer with 20 or more employees: Your employer coverage is primary -- it pays first. Medicare would be secondary. You can delay Part B enrollment without penalty as long as you have active employer coverage based on current employment.

Employer with fewer than 20 employees: Medicare is primary -- it pays first. Your employer plan pays second. In this case, you should enroll in Medicare at 65 to avoid coverage gaps and ensure your employer plan pays correctly.

When you have both Medicare and employer coverage, one plan pays first (primary) and the other pays second (secondary). The primary payer processes the claim first; the secondary payer covers some or all of the remaining costs.

Large employer (20+ employees): Employer plan is primary, Medicare is secondary. If you do not enroll in Medicare, your employer plan still covers you fully. If you do enroll, Medicare picks up some of what the employer plan does not cover.

Small employer (fewer than 20 employees): Medicare is primary. If you do not enroll in Medicare, your employer plan may pay as if Medicare had paid its share -- leaving you responsible for the Medicare portion. This can result in large unexpected bills.

Most people should enroll in Part A at 65 even if they have employer coverage -- because Part A is premium-free for most people and provides a useful secondary layer of coverage for hospitalizations.

Exception: If you are contributing to a Health Savings Account (HSA), enrolling in any part of Medicare (including Part A) makes you ineligible to contribute to your HSA. If maximizing HSA contributions is a priority, you may choose to delay all Medicare enrollment.

If you have employer coverage from an employer with 20+ employees based on your own or your spouse's current employment, you can delay Part B without penalty.

Key requirement: The coverage must be based on current employment -- not COBRA, retiree coverage, or coverage from a former employer. COBRA and retiree coverage do not qualify as a basis for delaying Medicare.

When your employer coverage ends (because you retire or lose the job), you have an 8-month Special Enrollment Period to enroll in Part B without a late penalty. This SEP begins the month after employment ends or coverage ends -- whichever comes first.

Important: Do not wait for COBRA to end before enrolling in Medicare. The SEP begins when employment ends -- not when COBRA ends. If you wait until COBRA runs out, you may miss your SEP and face a late enrollment penalty.

If your employer drug coverage is "creditable" (as good as Medicare's standard coverage), you can delay Part D enrollment without penalty. Your employer must provide an annual notice stating whether coverage is creditable.

When you lose employer coverage, you have a 63-day SEP to enroll in Part D without penalty.

• Determine your employer's size (20+ or fewer than 20 employees)
• Enroll in Part A at 65 (unless contributing to HSA)
• Decide on Part B based on employer size and coverage quality
• Confirm your employer drug coverage is creditable
• Plan your Medicare enrollment for when you retire
• Do not rely on COBRA as a basis for delaying Medicare

We do not offer every plan available in your area. Please contact Medicare.gov or 1-800-MEDICARE to get information on all of your options.